Need help or suggestions on drill bit vendor, manufacturer and steel.

admin

I am looking to make a couple of axle spacers for a 1976 HD bobber build that I am working on.  The original factory rear axle is 17mm diameter.  I am having a hard time finding correct spacers as I have converted the motorcycle to a hardtail.  It appears that most guys complete this conversion and swap to a later 3/4" diameter axle so that can run more modern disc brake rear setups.  My plan was to keep the factory drum brake rear but need to get the sprockets lined up properly.I was thinking of getting a properly sized metal cylindrical slug (aluminum or steel) and drilling a 17mm hole through the center.  I was hoping to use my floor standing drill press, and the machinist vise to properly center the slug and drill the hole.  Then I could cut the slug to the appropriate length based on the needed dimensions of the spacer.  Voila, custom made axle spacers.  Would this work?  Any suggestions on proper techniques?Advice where to buy the drill bits?What brand to buy?What type of tool steel to look for in a drill?Any suggestions on cutting speed for this diameter hole?Thanks.
Reply:I buy mine from Fastenal, although grainger has a good selection also.  Type of steel depends on material.  Aluminum drilling does not require as hard of bit as steel or hardened steel.  I my self use a lot of cobalt bits because they stay sharp.  Just becareful not to bind them or they will break.  On a whole that size I like to step up incriments. Drill speed is like people small and fast and big and slow.  As long as your drill press is of decent size you will have no problems.  Stepping up in sizes can make up for an undersized drill press also.Millermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:Thanks farmshop.  Any suggestions on how to step up?  Can I run every other size?  Every third or fourth?  Where would you figure is a good baseline place to start from when thinking about drilling out to 17mm?I was hoping to use Al but was worried about the dissimilar metals.  Do you think the grease applied to the axle shaft would provide enough of a barrier to prevent any reaction from occurring between the Al spacers and the steel axle shaft?
Reply:My drill press I would start at 3/8  and go up from there. I would go to 17mm in 3 or four steps.  once you start youll be able to tell how its going. I think there is some specific grease for that kind of stuff kind of like de ox for electrical.  If nothing else brass or bronze might be a thought.Millermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:Brass would be pretty cool.  I plan to use brass accent parts in some areas of the bike.  That could fit the bill nicely.  I assume brass would be much softer and easier drilling, compared to the steel.Again, thanks for the help farmshop.
Reply:Brass would drill like aluminum.  Good sharp bit like butter.  Just don't force bit in too fast or the chippings can bind up and depending on wall thickness give you grief.Millermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:Milwaukee Steel Hawg annular cutter in 11/16". Short one is reasonably priced, but is limited to about 1/2" thick steel. They make one for thicker steel as well. If you're cutting aluminum you can use a bimetal hole saw, but you'll need a flow of coolant or lots of WD40 to keep the chips from clogging. A trick is to drill one or two small holes just inside the radius of the cut to let the chips fall through.